Safety valves



y 1967 M. R. SCHOTT 3,317,182

SAFETY VALVES Filed July 24, 1964 United States Patent s 2 Claims. (Cl. 251-68) This invention relates to safety valves and particularly to' safety valves of the two-position type.

This invention concerns two-position fluid valves adapted to maintain a fluid passage either totally open or totally closed, but having no stationary intermediate position. Such devices find wide application in many industrial, aeronautic, automotive, and other fields. The present invention is particularly, but not exclusively, directed towards valves designed for use as safety means in the devices in which they are incorporated. The term safety means is here intended to include devices for halting or starting an operation in response to a given condition.

It is an object of this invention to improve the dependability of such switching operations.

It is another object herein to achieve the forceful switching of such valves through the agency of a relatively low-energy triggering action.

Yet another object of the present invention is to selectively permit either the stability or sensitivity of a safety valve to be easily regulatable.

The preferred embodiment of the present invention comprises principally: an obturator maintained, by biassing means, in that one of its extreme positions in which it is intended to remain during the normal operation of the installation in which it is incorporated; an energy accumulating means which is more powerful than said biassing means and which is mounted so as to be placed in a high potential energy state by an arming movement and then to be locked in this state; and a triggering means for unlocking the accumulator, for example in response to a signal, so as to permit the stored energy to be transformed into kinetic energy and to be so directed as to switch the obturator into its other extreme position (closed or open).- The energy accumulator is preferably established in an overshoot arrangement, i.e. the accumulating means has its maximum potential energy when it is in a state of unstable equilibrium, while the locking position is defined by an abutment which holds said accumulating means at a point just beyondits unstable equilibrium position; said triggering means being arranged so as to be able to move said accumulating means from'its abutment point back through its unstable equilibrium position, after which said accumulating means will continue to move, delivering all of its stored energy to switch said obturator.

The present invention consists in certain other elements preferably used in combination with the elements described above.

This invention is particularly directed to certain embodiments of the present invention as well as to certain uses thereof, in particular as safety mechanisms.

These and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description when taken together with the attached drawings in which:

FIGS. 1 to 3 are longitudinal cross-sectional views of a preferred embodiment of the present invention at various instants in its operating cycle.

The embodiment shown in the figures is a two-position safety valve which is normally in the position shown in FIG. 1. In this position, the valve, which may be installed in any type of device requiring a supply of fluid to a certain element only under unusual conditions, serves to isolate a supply of fluid in pipe 1 from an inlet pipe 2 for said certain element. Pipes 1 and 2 are formed in the main housing 3 of the valve and are isolated from one another by an obturator constituted by a valve 4 and its seating 5 formed integrally with housing 3. The obturator is maintained in the closed position of FIGS. 1 and 2 through the agency of biassing means which, in the present embodiment, is constituted principally by a compressed coil spring 6 held between an inner wall of housing 3 and a cylindrical guide bearing 7 rigidly connected to valve 4. secondarily, the valve is maintained closed by the differential pressure produced by the liquid introduced through pipe 1 due to the fact that the crosssectional area D, of the portion of valve 4 exposed to the liquid is greater than the area D at the portion of hearing 7 exposed to the liquid. It should be appreciated that bearing 7 is considered to be a portion of valve 4.

For opening the obturator in response to a signal, an energy accumulating means is provided in association with said obturator in such a position as to act in opposition to said biassing means. Said accumulating means is con stituted so as to generate when triggered, a greater force than that produced by the biassing means.

The accumulating means is arranged so as to be placed in its highest potential energy state, rearming maneuver, which may be and to then be bolted, or locked, in until being actuated by said triggering executed manually, a cocked position means. 1

The accumulating means is further preferably arranged to be of the overshoot type, i.e. so that its cocked, or locked position is slightly beyond its point of unstable equilibrium. It is also preferable that, that point of unstable equilibrium correspond with the maximum potential energy position of the accumulating means. Such an by simply moving it the small distance from its locked position back through its unstable flow from pipe 1 to pipe need only deliver a small It results, therefore, that the triggering means can be made quite small and can be made very sensitive to its input signal.

One form which such accumulating means and triggering means may take are shown in the figures, with FIG. 1 showing the accumulating means in its locked state, FIG. 2 showing it at its unstable equilibrium point, and FIG. 3 showing it after having converted its stored energy into kinetic energy to open valve 4.

The accumulating means is disposed in an auxiliary housing 8 connected to housing 3 in a position where the interior of housing 8 is opposite the driving rod 9 of valve In order to compress spring 10 so as to place it in its high potential energy state, guide member 11 is harnessed at one end by a connecting rod 12 to an oil-center point of a balance wheel 13 pivotally mounted for free rotation about a point 0 the latter point being situated on the longitudinal axis XX of valve 4, seat 5, and rod 9, and the axis of rotation of wheel 13 being perpendicular to axis XX. Wheel 13 may be rotated by any suitable crank means, not shown, extending to the exterior of housing 8.

Balance wheel 13 includes a radial bearing surface 13a arranged so that it will come to abut against stop member 14 when wheel 13 has rotated just beyond its unstable equilibrium point, i.e. the position where point 0 lies on axis XX. Thus when wheel 13 is stopped by member 14, point 0 will have moved slightly to one side of line XX, being spaced therefrom by a distance e. When member 14 abuts against surface 13a, the accumulating means is in its locked condition because it is prevented from moving in one direction by member 14 and from moving in the other direction by the reaction force of compressed spring 10.

The stop member 14 is preferably made adjustable, for example by means of a screw thread, as shown in the drawings, so that the distance e can be adjusted in order to vary the sensitivity of triggering, and the stability of locking, of the accumulating means.

In order to trigger the accumulating means so as to cause it to release its stored energy, it is only necessary to induce a small counterclockwise rotation of wheel 13 which will move pivot point 0 back to the other side of line XX from its locked position. The energy stored in spring will then be released, causing wheel 13 to continue its counterclockwise rotation until either spring 10 has given up all of its energy or has traveled as far as it can.

Such triggering means are constituted in the present embodiment by a plunger activated by a control device 16, which may for example be an electromagnetic solenoid connected to urge plunger 15 downward whenever the solenoid receives a predetermined command signal. The triggering is also constituted 'by a second radial bearing wall 13b on wheel 13 arranged to be directly in the path of travel of plunger 15 so as to rotate wheel 13 when plunger 15 is urged downward. With this arrangement, the downward movement of plunger 15 causes wheel 13 to rotate in the desired direction until passing its point of unstable equilibrium. FIG. 2 shows the plunger in contact with wall 131) and having rotated wheel 13 from its FIG. 1 position to its unstable equilibrium position. FIG. 3 shows the wheel having moved beyond its unsable equilibrium position and having rotated under the influence of spring 10 (plunger 15 and wall 13b no longer being in contact) until being stopped by the abutment of the rim of cylinder 11 against the end wall surrounding the opening in housing 3. This expansion of spring 10 urges rod 12 forward, thus advancing rod 9 and separating valve 4 from seat 5 so as to permit fluid to fiow from pipe 1 to pipe 2.

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While a particular embodiment of the present invention has been shown and described herein, it should be understood that this was for purposes of illustration only and that many other modifications would occur to one skilled in the art. For example the positions of said biassing means and accumulating means could be interchanged in order to arrive at a normally-open valve which is closed by a command signal. Therefore, it is intended that the coverage of the present invention be limited only by the scope of the attached claims.

What I claim is:

1. In combination with a fixed structure forming a closed fluid path, a two position valve device which comprises,

an obturator disposed in said path so as to be able to move between two extreme positions, in one of which positions it blocks said path and in the other of which positions it unblocks said path,

biassing means associated with said obturator for maintaining it in one of its extreme positions in which it is to normally remain,

a member pivoted in said fixed structure about a first axis carried by said fixed structure and perpendicular to the direction of movement of said obturator,

a link pivotally connected at one end thereof to said member about a second axis parallel to the first one carried by said member at a distance from said first axis, the other end of said link being located opposite said obturator,

an energy accumulating spring capable of exerting a force greater than said biassing means, said spring being interposed between said other end of said link and said fixed structure to urge said other end of said link toward said obturator for moving the latter into its other extreme position, said energy accumulating spring being adapted to be subjected to its maximum deformation when the plane passing through said two axes is in line with the direction of the thrust of said spring and said member is in an unstable position,

an abutment carried by said fixed structure adapted to cooperate with said member for holding it just past said unstable position, and

triggering means for rotating said member beyond said unstable position, thus releasing said energy accumulating spring.

2. A device according to claim 1 wherein said abutment is adjustable in position within certain limits.

References Cited by the Examiner UNITED STATES PATENTS M. CARY NELSON, Primary Examiner.

R. C. MILLER, Assistant Examiner, 

1. IN COMBINATION WITH A FIXED STRUCTURE FORMING A CLOSED FLUID PATH, A TWO POSITION VALVE DEVICE WHICH COMPRISES, AN OBTURATOR DISPOSED IN SAID PATH SO AS TO BE ABLE TO MOVE BETWEEN TWO EXTREME POSITIONS, IN ONE OF WHICH POSITIONS IT BLOCKS SAID PATH AND IN THE OTHER OF WHICH POSITIONS IT UNBLOCKS SAID PATH, BIASSING MEANS ASSOCIATED WITH SAID OBTURATOR FOR MAINTAINING IT IN ONE OF ITS EXTREME POSITIONS IN WHICH IT IS TO NORMALLY REMAIN, A MEMBER PIVOTED IN SAID FIXED STRUCTURE ABOUT A FIRST AXIS CARRIED BY SAID FIXED STRUCTURE AND PERPENDICULAR TO THE DIRECTION OF MOVEMENT OF SAID OBTURATOR, A LINK PIVOTALLY CONNECTED AT ONE END THEREOF TO SAID MEMBER ABOUT A SECOND AXIS PARALLEL TO THE FIRST ONE CARRIED BY SAID MEMBER AT A DISTANCE FROM SAID FIRST AXIS, THE OTHER END OF SAID LINK BEING LOCATED OPPOSITE SAID OBTURATOR, AN ENERGY ACCUMULATING SPRING CAPABLE OF EXERTING A FORCE GREATER THAN SAID BIASSING MEANS, SAID SPRING BEING INTERPOSED BETWEEN SAID OTHER END OF SAID LINK AND SAID FIXED STRUCTURE TO URGE SAID OTHER END OF SAID LINK TOWARD SAID OBTURATOR FOR MOVING THE LATTER INTO ITS OTHER EXTREME POSITION, SAID ENERGY ACCUMULATING SPRING BEING ADAPTED TO BE SUBJECTED TO ITS MAXIMUM DEFORMATION WHEN THE PLANE PASSING THROUGH SAID TWO AXES IS IN LINE WITH THE DIRECTION OF THE THRUST OF SAID SPRING AND SAID MEMBER IS IN AN UNSTABLE POSITION, AN ABUTMENT CARRIED BY SAID FIXED STRUCTURE ADAPTED TO COOPERATE WITH SAID MEMBER FOR HOLDING IT JUST PAST SAID UNSTABLE POSITION, AND TRIGGERING MEANS FOR ROTATING SAID MEMBER BEYOND SAID UNSTABLE POSITION, THUS RELEASING SAID ENERGY ACCUMULATING SPRING. 